CVE-2025-39845

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()

MEDIUM

5.5

CVSS Score

Published: September 19, 2025 at 03:26 PM UTC

Updated: October 19, 2026 at 09:10 PM UTC

6 products affected across 3 vendorsLinux KernelDebian LinuxSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP Firmware

Using Linux by Linux?

Get instant alerts when new vulnerabilities affect Linux - before attackers find them.

Real-time alertsTrack your software stackFree plan available

Start Free Sign In

Severity

MEDIUM5.5

Exploit prediction

EPSS 0.2%

Description

In the Linux kernel, the following vulnerability has been resolved: x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure page tables are properly synchronized when calling p*d_populate_kernel(). For 5-level paging, synchronization is performed via pgd_populate_kernel(). In 4-level paging, pgd_populate() is a no-op, so synchronization is instead performed at the P4D level via p4d_populate_kernel(). This fixes intermittent boot failures on systems using 4-level paging and a large amount of persistent memory: BUG: unable to handle page fault for address: ffffe70000000034 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI RIP: 0010:__init_single_page+0x9/0x6d Call Trace: <TASK> __init_zone_device_page+0x17/0x5d memmap_init_zone_device+0x154/0x1bb pagemap_range+0x2e0/0x40f memremap_pages+0x10b/0x2f0 devm_memremap_pages+0x1e/0x60 dev_dax_probe+0xce/0x2ec [device_dax] dax_bus_probe+0x6d/0xc9 [... snip ...] </TASK> It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap before sync_global_pgds() [1]: BUG: unable to handle page fault for address: ffffeb3ff1200000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI Tainted: [W]=WARN RIP: 0010:vmemmap_set_pmd+0xff/0x230 <TASK> vmemmap_populate_hugepages+0x176/0x180 vmemmap_populate+0x34/0x80 __populate_section_memmap+0x41/0x90 sparse_add_section+0x121/0x3e0 __add_pages+0xba/0x150 add_pages+0x1d/0x70 memremap_pages+0x3dc/0x810 devm_memremap_pages+0x1c/0x60 xe_devm_add+0x8b/0x100 [xe] xe_tile_init_noalloc+0x6a/0x70 [xe] xe_device_probe+0x48c/0x740 [xe] [... snip ...]

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Debian Linux · Debiandrupal

95%

11.0

Linux Kernel · Linux

95%

5.13 ≤ v < 5.15.1925.16 ≤ v < 6.1.1516.13 ≤ v < 6.16.66.2 ≤ v < 6.6.1056.7 ≤ v < 6.12.466.17 6.17 rc1 6.17 rc2 6.17 rc3 6.17 rc48d400913c231bd1da74067255816453f96cd35b0

Vendor states this is fixed in 26ff568f390a531d1bd792e49f1a401849921960 (fixed)

Vendor states this is fixed in 5f761d40ee95d2624f839c90ebeef2d5c55007f5 (fixed)

Vendor states this is fixed in 6659d027998083fbb6d42a165b0c90dc2e8ba989 (fixed)

Vendor states this is fixed in 6bf9473727569e8283c1e2445c7ac42cf4fc9fa9 (fixed)

Vendor states this is fixed in 744ff519c72de31344a627eaf9b24e9595aae554 (fixed)

Vendor states this is fixed in b7f4051dd3388edd30e9a6077c05c486aa31e0d4 (fixed)

Vendor states this is fixed in 5.13 (unaffected)

Vendor states this is fixed in 5.15.192 (unaffected)

Vendor states this is fixed in 6.1.151 (unaffected)

Vendor states this is fixed in 6.12.46 (unaffected)

Vendor states this is fixed in 6.16.6 (unaffected)

Vendor states this is fixed in 6.17 (unaffected)